In the same way that consumers spend more with credit cards than with cash because of the convenience factor (and because it's more abstract -- you don't "feel" the spending as much), Apple Pay may drive up purchases even further still, because payment and tipping is just a one-tap proposition.

Also: Because payments are faster, and because the cashier becomes somewhat redundant, retail stores should be able to reduce staff and save a bundle.

And finally, Apple Pay is massively faster than credit card, cash or check transactions. The more people use it, the faster lines in stores will go for all customers.

Financial Institutions

So far, Apple has bragged vaguely about lining up more than 500 US banks and other financial institutions, and specifically about American Express, Bank of America, Capital One, JPMorgan Chase, Citibank, Wells Fargo, Barclaycard, Navy Federal Credit Union, PNC, U.S. Bank and USAA. The companies now on board together process more than 83% of the credit card transactions in the US -- and that's before they even launched.

Most participating banks and credit unions that have commented on Apple Pay so far give it rave reviews, saying (as in the case of a Navy Federal Credit Union executive) that Apple Pay is "convenient, secure and private."

Of course, major retailers have been taken to the cleaners by hack attacks recently. And guess who pays for that? The financial institutions take the hit.

Like Google Wallet, Apple Pay uses tokenization, which means the user's credit card information is never shared with the store. The user is authenticated by the iPhone using Touch ID. Then a one-time-only string of randomized data is generated for that transaction, passed right through the store's system and on to the bank. In fact, the credit card number isn't stored on the phone at all, nor even on Apple servers -- Apple doesn't even know what you bought, where you shopped or how much you spent.

Future hacks of the kind that have been pandemic in retail will not include any information for Apple Pay users, because there's no data on the stores' servers to steal. The more transactions that happen with Apple Pay, the less money the banks lose.

Apple Pay is the most secure mobile payment system yet -- more secure even than the chip-and-pin systems used outside the US, and way more secure than the magnetic credit card system used by most credit card transactions. And it's more secure than Google Wallet because of the widespread use of Touch ID fingerprint identification.

Another huge benefit is that Apple Pay is so convenient (and will lead the whole industry to greater use of mobile transactions) that many cash transactions will be replaced with Apple Pay. This is obviously a huge boon for the banks, which get nothing when people use cash.

iOS App Makers

Apple announced last week that the company's new iPad Air 2 and iPad mini 3 tablets will work with Apple Pay, but not in brick-and-mortar retail locations -- just in apps. And, of course, Apple Pay-supporting iPhones will work in apps.

Because Apple Pay will make in-app purchases trivially easy, people will spend more and app makers will have much higher monetization.

The Downside

Of course, Apple Pay isn't all good.

It adds risks for iPhone users, who are already singled out for higher rates of attack and theft. Now, instead of just stealing a wallet and spending the cash and using the credit cards, an iPhone replacement for a wallet now requires the participation of the owner, possibly at gunpoint.

It also takes control away from retailers, who will not be able to harvest personal data of customers as they would prefer to do.

Still, Apple Pay is going to change everything, and on the whole for the better. And not just for participating users. For just about everybody.